Hitherto, for a photographic light-sensitive material, a wet development has been applied using a developing solution after photographing. However, the method has the following inconveniences, and improvement has been desired.
[1] Because development, bleaching, fixing, and drying are carried out, a long time is required for the development processing.
[2] Because plural tanks containing a developing solution are required, a processor cannot be made small in size and light in weight.
[3] Inconveniences, such as the replenishment of a developing solution, the disposal of processing liquids, washing of developing tanks, etc., are required.
For improvement thereof, photographic light-sensitive materials that are processed using a development method by heating (hereinafter, occasionally referred to as "heat development") to a temperature of from 80 to 150.degree. C. are proposed, as described in, for example, U.S. Pat. No. 3,152,904, U.S. Pat. No. 3,457,075, JP-B-43-4921 ("JP-B" means an examined Japanese patent publication), and JP-B-43-4924. One example is a method of previously incorporating a precursor for a developing agent in a light-sensitive layer, decomposing the precursor by heating, to form a developing agent, and subjecting to development. In such a heat-developing system, the development processing may be carried out by only applying heat, whereby the processing can be carried out in a short time and a processor can be small in size. Furthermore, there are no inconveniences with the replenishment and the disposal of a developing solution.
However, when the light-sensitive material of this system was applied to a printing light-sensitive material, when 4 plates (blue, green, red, and black plates) were piled up, there was a problem that color discrepancies were caused by the dimensional change that occurs during the heat development. To solve the problem, a method of heat treating under a low tension is known hitherto, as described, for example, in JP-A-60-22616 ("JP-A" means unexamined published Japanese patent application), JP-A-64-64883, JP-A-54-158470, and U.S. Pat. No. 2,779,684. By conducting the low-tension heat treatment to a support, the dimensional change between before and after the heat development could be reduced, but accompanying the heat treatment, inferior flatness (slackening in the middle of a support, and undulation) occurred. This is a large problem for a photographic support that is required to have high flatness.